In mobile, wireless networking, there can be a large number of stationary devices and mobile devices at an incident scene. Exemplary stationary devices and mobile devices can include surveillance cameras, two-way radios, lapel worn cameras/microphones, smart glasses, tablets, Long Term Evolution (LTE) devices, devices in command vehicles, unmanned aerial vehicles (UAVs), etc. The stationary devices and mobile devices can dynamically form a mesh network using Wireless Local Area Network (WLAN) technologies to enable communications among the network nodes and provide access to mission-critical services and information. Additionally, the services can include broadband access to a backend network via a gateway (e.g. through a high speed gateway in the command vehicle), access to video streams of surveillance cameras and other real-time mission critical information or services made available by one of the network nodes or the backend network. The use of mesh networks improves communications and availability of mission critical services at incident scenes. These networks can be used both to offload the backend communications resources, as well as a primary method of communications at the incident scene when the incident scene is disconnected from backend infrastructure services.
One problem in such incident mesh networks is that the network nodes may form two or more independent IBSSs (Independent Basic Service Sets) because they are out of range of each other and/or use different WLAN channels. This leads to separate clusters, or separate mesh networks with a same SSID (Service Set Identification). Another reason for separated mesh clusters could be the use of different wireless communication technologies by groups of nodes, such as IEEE 802.11 and variants thereof (Wi-Fi), 802.15.1 (Bluetooth), 802.15.4 (ZigBee), and 802.16 (WiMAX). Nodes in separate clusters cannot communicate with each other and may not even be aware of each other, including the available services in the other cluster(s). Hence, available mission-critical information and services cannot be fully utilized across all available devices.
Another reason for the unintended formation of disjoint clusters can occur when strong security mechanisms are added to the ad hoc networking protocols. Many commonly deployed ad hoc networks overlook security completely while other ad hoc network solutions provide overly simplistic security models (such as give every node the same key) which often prove impractical and insecure in real life applications. When it is assumed that all nodes have access to the same key used to secure the Media Access Control (MAC) layer, or when no security is used, bridging between groups of nodes occurs inherently whenever a bridging node is in range of both groups, because in these systems all route requests are broadcast and as long as there is a path between any two nodes they are able to find each other and communicate. However, once stronger security is required, it is not usually possible to simply broadcast route requests that all neighboring nodes are able to receive. Even if all nodes are in range of each other (in a fully connected topology) by adding strong security, this immediately breaks the inherent bridging that typically occurs in an ad hoc mesh networks. This results in a much greater likelihood that disjoint clusters occur.
Further, when strong security is applied to ad hoc networks, various functions like “service discovery” break because some nodes can no longer talk to each other. Common methods like multicast Domain Name System (MDNS) and DNS Service Discovery (DNS-SD) rely on the existence of a single broadcast domain on which service discovery messages can be broadcast or multicast. As discussed above, adding strong security means that a single broadcast domain is much more unlikely due to the natural clustering that would occur simply because of the added security.
In summary, disjoint clustering of ad hoc network nodes at an incident scene can occur for many reasons such as nodes are out of range of each other, nodes not originally in coverage with an existing cluster choose a different channel, nodes may use different wireless technologies, Bluetooth Wi-Fi, Zigbee, WiMAX, etc.; arriving nodes choose only one node to authenticate with and exchange multicast broadcast keys—even if they choose more than one, unless they exchange keys with every node present they cannot guarantee that clustering does not occur; etc.
Regardless of the reason, the occurrence of disjoint clusters is a serious problem that can prevent communications necessary to effectively and safely manage an incident scene. Current WLAN and Mesh Network protocols and standards (such as IEEE 802.11s and ZigBee) do not address the dynamic bridging of disjoint network clusters and cannot enable communications and services across such network clusters
Accordingly, there is a need for mobile dynamic mesh cluster bridging method and apparatus at incident scenes.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.